Dynamic Payload as per the Id Provided in params

I am working on a Backend Project, and also created multiple APIs.

In one of my API i want dynamic payload as per the id in the params provided & and i am not able to implement it,

example of the requirment
api/v1/acc/{1}
then payload should be 
{
  "name":"String"
}

if api/v1/acc/{2}
{
  "age":"number"
}


the the request.body should change dynamiclly as per params id,

Soo can anyone help me with it,
Thanks in advance